Process for the dealkylation of aromatic hydrocarbons

ABSTRACT

AROMATIC HYDROCARBONS ARE DELKYLATED IN THE PRESENCE OF STEAM AND A NICKEL-BERYLLIUM OXIDE CATALYST HAVING A NICKEL CONTENT OF FROM 5 TO 80 WEIGHT PERCENT. THE CATALYST IS PREPARED BY IMPREGNATING BASIC BERYLLIUM CARBONATE, BERYLLIUM OXIDE, OR BERYLLIUM HYDROXIDE WITH AN AQUEOUS SOLUTION OF A NICKEL COMPOUND SUCH AS NICKEL NITRATE, DRYING THE RESULTING PRODUCT, CALCINING IT AT ABOUT 500*C. IN A STREAM OF INERT GAS, THEN PELLETIZING IT, AND REDUCING THE RESULTANT POWDER WITH HYDROGEN. THE DEALKYLATION IS PREFERABLY CARRIED OUT AT A TEMPERATURE OF 350-500*C. THE STEAM AND AROMATIC HYDROCARBON ARE RESPECTIVELY EMPLOYED IN A MOLAR RATIO OF ABOUT 3-19 TO 1. THE DEALKYLATION IS PREFERABLY CARRIED OUT A SPACE VELOCITY OF ABOUT 1500 TO 6000 HR.-1 BASED ON THE TOTAL VOLUME OF STEAM AND AROMATIC HYDROCARBON VAPOR, AND AT A LIQUID HOURLY SPACE VELOCITY OF THE AROMATIC HYDROCARBON OF ABOUT 0.8 TO 4.3. SURPRISINGLY, DEALKYLATION OCCURS WITH LITTLE DISINTEGRATION OF THE BENZENE RING.

United States Patent Office Patented Jan. 11, 1972 3,634,532 PROCESS FOR THE DEALKYLATION F AROMATIC HYDROCARBONS Yoshisada Ogino, Akira Igarashi, and Michio Tsuchiya,

Aromatic hydrocarbons which are preferably used in the present invention include, for example, toluene, 0-, m-, and p-xylenes, ethyl-benzene, cumene and methylnaphthalen. These may be used either singly or in the form Sendai-shi, Japan, assignors t0 Idemitsu Kosan Co., 5 of fixtures- Ltd., and Mitsubishi Petrochemical Company Ltd. The Catalyst p y in the present invention is P No Prawing. Filed Oct. 5, 1970, Ser. No. 78,234 pared in such a manner that basic beryllium carbonate Clalms P a applicafioll p Apr. 9, 1970, is impregnated with an aqueous nickel nitrate solution, I 45/29777 dried and calcined at about 500 C. in the stream of an Us. Cl 260 672 3/58 5 Claims 10 inert gas such as nitrogen to obtain a powder, which is then pelletized and reduced with hydrogen. As a beryllium source for the catalyst preparation, beryllium oxide or beryllium hydroxide may also be employed instead of APSTRACT OF THE DISCLOSURE basic beryllium carbonate, and the nickel source is not Aromatic hydrocarbons are dealkylated in the presence limit d t i k l i t only, steam and a nickel-beryllium Oxide catalyst having 3 Thus, the catalyst used in the present invention is comnickel content of from 5 to 80 weight percent. The cataposed substanially of nickel and beryllium oxide. The Y 18 p p y lmpfegnatihg basic beryllium e b nickel content of the catalyst may range from 5 to 80 nate, beryllium oxide, or beryllium hydroxide with an w ight percent, aflueous Solution of a nickel compound Such as el 20 The dealkylation reaction of the present invention is r rying the resulting P calcining it at about desirably effected at about 350 to 500 C. at atmospheric a stream of inert gas, then PellefiZing and pressure or under an increased pressure. In the reaction, reducing the resultant powder with hydrogen. The dethe space velocity is preferably about 1,500 to 6,000 alkylation is preferably carried out at a temperature of hr. based on the total volume of the starting steam 35040 0 C. The steam and aromatic hydrocarbon are and the starting aromatic hydrocarbon vapor, and the respectively employed in a molar ratio of about 3-19 to 1. li uid hourly space velocity (L.H.S.V.) of the starting The dealkylation is preferably carried out a space velocaromatic hydrocarbon is preferably about 0.8 to 4.3. ity of about 1500 to 6000 hr? based on the total volume Ordinarily, the molar ratio of the starting steam to the of steam and aromatic hydrocarbon vapor, and at a liquid starting aromatic hydrocarbon is about 3-19 to l. hourly space velocity of the aromatic hydrocarbon of The present invention is illustrated in further detail about 0.8 to 4.3. Surprisingly, dealkylation occurs with h reinb low with reference to examples. little disintegration of the benzene ring.

EXAMPLES l-28 This invention relates to a process for the dealkylation Preparation of catalyst? of aromatic hydrocarbons. More particularly, the inven- A given amount of Powder of a desired Carbonate tion relates to a process for dealkylating aromatic hydrobasic carbonate) was addccl to an aqueous Solution c011- carbons by use of a nickel-beryllium oxide catalyst in the mining a given amount of mckel nitrate The mixture Was presence of steam. heated gently on a water bath and evaporated to dryness. In the prior art processes for dealkylating aromatic 40 Then, the resultant miXtllre 0f the carbonate and the hydrocarbons, it is commonly known that th dealkylanitrate was taken out, dried at about 100. C. and calcined tion reactions are carried out thermally or catalytically in at C for 2 hours in the Stream Of Ilitfcgen to Obtain the presence of hydrogen to obtain, together with sat- 3 Powder containing about 20 Weight Percent of nickelurated hydrocarbons, aromatic hydrocarbons having car- The Tesllltent POWcler Wes PcHetiY-ed under a Pressure of bon numbers less than those of the corresponding starting 4,000 kgi/cm-z- The Pellets Were crushed and sieved to aromatic hydrocarbons. In addition to the above methods, grains of 1 to 2 in Size, Which Were then reduced dealkylation of aromatic hydrocarbons by use only of 2 hours with hy at in e dealkylasteam is known, but these prior art processes usually n reaction tubecause so remarkable disintegration of the aromatic ring Dealkylation reactions: that they are not carried out to the extent of ones satis- The aromaitc hydrocarbons used as starting materials faction. were toluene, ethylbenzene, o-, m-, and p-xylenes and We have made an extensive research to find catalysts Cumene. The dealkylation reactions of these were ineffective in such a dealkylation process wherein steam is dividually effected at a temperature ranging from 347 used instead of expensive hydrogen. As the result, we to 450 C. and at atmospheric pressure, using a convenhave found that an aromatic hydrocarbon having one tional flow typ'e apparatus containing 5 ml. of the catalyst or more alkyl groups can be effectively dealkylated with prepared in the above-mentioned method. The analyses the benzene nucleus mostly preserved in the presence of of the product liquids and gases after the dealkylation steam by using a nickel-beryllium oxide catalyst, while reactions were carried out by a gas chromatographic the splitted alkyl groups are converted mainly into carbon method. The conditions and the results of the dealkyladioxide and hydrogen. tion reactions are shown in Table 1.

TABLE I Preser- Molar Liquid Convervation ratio of product sion to ratio of Starting Reaction steam to compoliquid aromatic Gas product composition aromatic temperaaromatic sition product nucleus (mol percent) hydroture L.H.S.V. hydro- Liquid (mol (mol mol Example carbon C.) (hL- carbon product percent) percent) percent) CO CH4 002 H;

1 Toluene. 450 2.3 6.1 Benzene 40 93.2 3.4 0.9 24.6 71.1 2 o-Xylcne 450 2.3 6.9 36 95.1 2.6 1.2 22.3 73.9 3 p-Xylene 450 2.3 7.1 ggi fjgg 57 98.1 5.0 2.4 26.8 65.8

TABLE I.Cnlt1inued Preser- Molar Liquid Couvervation ratio of product sion to ratio of Starting Reaction steam to eompoliquid aromatic Gas product composition aromatic temperaaromatic sition product nucleus (mol percent) hydroture L.H.S.V. hydro- Liquid (mol mol (mo Example carbon C.) (hr. carbon product crcent) percent) percent) 00 CH4 CO; H;

4 m-Xyleue- 450 1.2 0.8 {33 333 57-00 04.1 2.8 0.0 22.7 73.0

Benzene 25 450 3.8 3 7 {.lg 75 20 -100 2.4 1.0 21.9 74.7

. enzene 20 450 2.2 0.3 80 52-58 08.0 2.7 0.8 23.2 73.3 7 .110 450 1.8 8 4 {,%gi f 48-49 00.4 2.5 1.2 22.0 73.7 8 -.do 450 1.3 12.8 {%2?::: 04-05 00.8 2.7 1.4 23.2 72.7 0 do 450 0.86 18.0 g?gg::: 04 87.4 1.8 0.0 24.3 73.0 10 do 450 4.3 0.8 {153 5533 17-18 02.2 3.4 22.2 74.4

Benzene. 13-14 11 -.do 420 2.2 6.8 {Toluene 87% 41 07.0 1.1 0.5 25.4 73.0 12 ..do 300 2.2 0.8 23 00.4-00.8 0.0 25.5 73.0

Benzene. 4-5 13 do-.. 300 2. 2 0. 8 {Toluem 9H5 8 -100 20. 8 73. 2 14 r th l 450 1.1 09-70 00-00.0 3.0 2.4 20.0 73.1

enzene. 15 do 450 3.8 03.0 4.4 1.3 20.1 74.2 10 10 450 2.2 54-55 04.5 4.1 2.3 21.3 72.3 17 05 450 1.3 58 88.2 2.4 1.8 22.0 73.2 18 .110 450 4.3 20 04.3 4.31 2.00 22.3 70.7 10 do 420 2.2 003-100 3.03 1.17 22.7 73.1 20 do 300 2.2 10-17 09. 3-100 2.08 0.52 23.4 74.0 21 do 300 2.2 5.5 -100 1.2 23.0 74.0

3 22 Cumene.-. 500 2.2 16 05 -100 45 20 m-Xylene. 450 2.5 6.8 {331 5333 3.0 08 27- "do..." 450 2. 5 0- 8 {3305333 g}, 7- 3 00 Benzene. 17 28. do 450 2.1 0.8 {Tolueneflm 83 1.8 04

N0'1E.In Example 26, beryllium oxide was used as the be yllium source; in Example 27, beryllium hydroxide was used as the beryllium source;

in Example 28, the calcination of catalyst was effected at 850 0.

Notes: In Example 26, beryllium oxide was used as the beryllium source. In Example 27, beryllium hydroxide was used as the beryllium source. In Example 28, the calcination of catalyst was effected at 850 C.

What we claim is:

1. A process for the dealkylation of an aromatic hydrocarbon, characterized in that the dealkylation is effected by use of a nickel-beryllium oxide catalyst in the presence of steam.

2. A process for the dealkylation of an aromatic hydrocarbon according to claim 1, wherein said dealkylation is carried out at a temperature of about 350 to 500 C. at atmospheric pressure or under an increased pressure.

3. A process for the dealkylation of an aromatic hydrocarbon according to claim 2, wherein said dealkylation is carried out at the space velocity of about 1500 to 6000 hr.- based on the total volume of the starting steam and the starting aromatic hydrocarbon vapor and at the liquid hourly space velocity (L.H.S.V.) of the starting aromatic hydrocarbon of about 0.8 to 4.3.

4. A process for the dealkylation of an aromatic hydracarbon according to claim 1, wherein said aromatic hydrocarbon is at least one member selected from the group consisting of toluene, o-, mand p-xylenes, ethylbenzene, cumcne and methyl naphthalene.

5. A process for the dealkylation of an aromatic hydrocarbon according to claim 1, wherein said nickelberyllium oxide catalyst is that which is obtained by impregnating a beryllium compound selected from the group consisting of beryllium basic carbonate, beryllium hydroxide and beryllium oxide with an aqueous solution of a water-soluble nickel compound, drying the impregnated mass and calcining it at about 500 C. in the-stream of an inert gas, forming the calcined product to suitable shape and then reducing it with hydrogen to have a catalyst substantially composed of nickel and beryllium oxide and having a nickel content of 5-80% by weight.

References Cited UNITED STATES PATENTS 3,033,777 5/ 1962 Moy et al. 260--672 3,261,876 7/1'966 Kovach 260672 3,449,460 6/ 1969 Tarham 260- 672 FOREIGN PATENTS 1,263,734 3/ 1968 Germany 260672 CURTIS R. DAVIS, Primary Examiner 

